#ifndef _RRSHADERS_HPP
#define _RRSHADERS_HPP
/*-------------------------------------------------------------------------
 * drawElements Quality Program Reference Renderer
 * -----------------------------------------------
 *
 * Copyright 2014 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 *//*!
 * \file
 * \brief Shader interfaces.
 *//*--------------------------------------------------------------------*/

#include "rrDefs.hpp"
#include "rrVertexAttrib.hpp"
#include "rrVertexPacket.hpp"
#include "rrFragmentPacket.hpp"
#include "rrPrimitivePacket.hpp"
#include "rrShadingContext.hpp"
#include "deString.h"

namespace rr
{

/*--------------------------------------------------------------------*//*!
 * \brief Vertex shader input information
 *//*--------------------------------------------------------------------*/
struct VertexInputInfo
{
	VertexInputInfo (void)
	{
		// sensible defaults
		type = GENERICVECTYPE_LAST;
	}

	GenericVecType	type;
};

/*--------------------------------------------------------------------*//*!
 * \brief Shader varying information
 *//*--------------------------------------------------------------------*/
struct VertexVaryingInfo
{
	VertexVaryingInfo (void)
	{
		// sensible defaults
		type		= GENERICVECTYPE_LAST;
		flatshade	= false;
	}

	// \note used by std::vector<T>::operator==() const
	bool operator== (const VertexVaryingInfo& other) const
	{
		return	type == other.type &&
				flatshade == other.flatshade;
	}

	GenericVecType	type;
	bool			flatshade;
};

typedef VertexVaryingInfo VertexOutputInfo;
typedef VertexVaryingInfo FragmentInputInfo;
typedef VertexVaryingInfo GeometryInputInfo;
typedef VertexVaryingInfo GeometryOutputInfo;

/*--------------------------------------------------------------------*//*!
 * \brief Fragment shader output information
 *//*--------------------------------------------------------------------*/
struct FragmentOutputInfo
{
	FragmentOutputInfo (void)
	{
		// sensible defaults
		type = GENERICVECTYPE_LAST;
	}

	GenericVecType type;
};

/*--------------------------------------------------------------------*//*!
 * \brief Vertex shader interface
 *
 * Vertex shaders execute shading for set of vertex packets. See VertexPacket
 * documentation for more details on shading API.
 *//*--------------------------------------------------------------------*/
class VertexShader
{
public:
											VertexShader		(size_t numInputs, size_t numOutputs) : m_inputs(numInputs), m_outputs(numOutputs) {}

	virtual void							shadeVertices		(const VertexAttrib* inputs, VertexPacket* const* packets, const int numPackets) const = 0;

	const std::vector<VertexInputInfo>&		getInputs			(void) const	{ return m_inputs;	}
	const std::vector<VertexOutputInfo>&	getOutputs			(void) const	{ return m_outputs;	}

protected:
											~VertexShader		(void) {} // \note Renderer will not delete any objects passed in.

	std::vector<VertexInputInfo>			m_inputs;
	std::vector<VertexOutputInfo>			m_outputs;
} DE_WARN_UNUSED_TYPE;

/*--------------------------------------------------------------------*//*!
 * \brief Fragment shader interface
 *
 * Fragment shader executes shading for list of fragment packets. See
 * FragmentPacket documentation for more details on shading API.
 *//*--------------------------------------------------------------------*/
class FragmentShader
{
public:
											FragmentShader		(size_t numInputs, size_t numOutputs) : m_inputs(numInputs), m_outputs(numOutputs) {}

	const std::vector<FragmentInputInfo>&	getInputs			(void) const	{ return m_inputs;	}
	const std::vector<FragmentOutputInfo>&	getOutputs			(void) const	{ return m_outputs;	}

	virtual void							shadeFragments		(FragmentPacket* packets, const int numPackets, const FragmentShadingContext& context) const = 0; // \note numPackets must be greater than zero.

protected:
											~FragmentShader		(void) {} // \note Renderer will not delete any objects passed in.

	std::vector<FragmentInputInfo>			m_inputs;
	std::vector<FragmentOutputInfo>			m_outputs;
} DE_WARN_UNUSED_TYPE;

/*--------------------------------------------------------------------*//*!
 * \brief Geometry shader input primitive type
 *//*--------------------------------------------------------------------*/
enum GeometryShaderInputType
{
	GEOMETRYSHADERINPUTTYPE_POINTS = 0,
	GEOMETRYSHADERINPUTTYPE_LINES,
	GEOMETRYSHADERINPUTTYPE_LINES_ADJACENCY,
	GEOMETRYSHADERINPUTTYPE_TRIANGLES,
	GEOMETRYSHADERINPUTTYPE_TRIANGLES_ADJACENCY,

	GEOMETRYSHADERINPUTTYPE_LAST
};

/*--------------------------------------------------------------------*//*!
 * \brief Geometry shader output primitive type
 *//*--------------------------------------------------------------------*/
enum GeometryShaderOutputType
{
	GEOMETRYSHADEROUTPUTTYPE_POINTS = 0,
	GEOMETRYSHADEROUTPUTTYPE_LINE_STRIP,
	GEOMETRYSHADEROUTPUTTYPE_TRIANGLE_STRIP,

	GEOMETRYSHADEROUTPUTTYPE_LAST
};

/*--------------------------------------------------------------------*//*!
 * \brief Geometry shader interface
 *
 * Geometry shader executes a list of primitive packets and outputs
 * a new set of vertex packets for new primitives.
 *//*--------------------------------------------------------------------*/
class GeometryShader
{
public:
											GeometryShader		(size_t numVaryingInputs,
																 size_t numVaryingOutputs,
																 GeometryShaderInputType inputType,
																 GeometryShaderOutputType outputType,
																 size_t numVerticesOut,
																 size_t numInvocations);

	virtual void							shadePrimitives		(GeometryEmitter& output, int verticesIn, const PrimitivePacket* packets, const int numPackets, int invocationID) const = 0;

	const std::vector<GeometryInputInfo>&	getInputs			(void) const { return m_inputs; }
	const std::vector<GeometryOutputInfo>&	getOutputs			(void) const { return m_outputs; }
	inline GeometryShaderInputType			getInputType		(void) const { return m_inputType; }
	inline GeometryShaderOutputType			getOutputType		(void) const { return m_outputType; }
	inline size_t							getNumVerticesOut	(void) const { return m_numVerticesOut; }
	inline size_t							getNumInvocations	(void) const { return m_numInvocations; }

protected:
	const GeometryShaderInputType			m_inputType;
	const GeometryShaderOutputType			m_outputType;
	const size_t							m_numVerticesOut;
	const size_t							m_numInvocations;

	std::vector<GeometryInputInfo>			m_inputs;
	std::vector<GeometryOutputInfo>			m_outputs;
} DE_WARN_UNUSED_TYPE;

// Helpers for shader implementations.

template<class Shader>
class VertexShaderLoop : public VertexShader
{
public:
					VertexShaderLoop	(const Shader& shader) : m_shader(shader) {}

	void			shadeVertices		(const VertexAttrib* inputs, VertexPacket* packets, const int numPackets) const;

private:
	const Shader&	m_shader;
};

template<class Shader>
void VertexShaderLoop<Shader>::shadeVertices (const VertexAttrib* inputs, VertexPacket* packets, const int numPackets) const
{
	for (int ndx = 0; ndx < numPackets; ndx++)
		m_shader.shadeVertex(inputs, packets[ndx]);
}

template<class Shader>
class FragmentShaderLoop : public FragmentShader
{
public:
					FragmentShaderLoop	(const Shader& shader) : m_shader(shader) {}

	void			shadeFragments		(FragmentPacket* packets, const int numPackets) const;

private:
	const Shader&	m_shader;
};

template<class Shader>
void FragmentShaderLoop<Shader>::shadeFragments (FragmentPacket* packets, const int numPackets) const
{
	for (int ndx = 0; ndx < numPackets; ndx++)
		m_shader.shadeFragment(packets[ndx]);
}

} // rr

#endif // _RRSHADERS_HPP